There is evidence that a fever is actually beneficial, and the reason is simple: the immune system fights infections better when the body is hotter. White blood cells are released in greater numbers from the bone marrow, and the cells do a better job of fighting the infection. Fever also improves the efficacy of another group of blood cells called natural killer cells, and it increases the ability of macrophages (“big eaters” in Greek) to ingest and destroy the invading cells.
